1. Technical Field
The present invention relates to the manufacture of face gears provided on the handle shaft of spinning reels; in particular the invention relates to methods of diecasting such face gears.
2. Description of Related Art
Generally spinning reels have a reel main body, a rotor supported for free rotation on the main body, and a spool that peripherally winds on fish line, provided forward of the rotor. The rotor rotates unitarily with a pinion gear provided peripherally on the spool axle. The spool reciprocates back and forth by means of a level-wind mechanism that is driven by an intermediate gear that meshes with the pinion gear. The pinion gear meshes with a face gear (master gear) provided on a handle rotation axle (handle shaft) that is orthogonal to the pinion gear, and is rotated by rotation of the handle. The face gear is usually formed incorporated with the handle shaft. Conventionally zinc alloys have been comparatively widely used as a material for cheaply manufacturing the face gear that includes the handle shaft, and for maintaining its strength.
Generally with spinning reels, designing the face gears to make them lightweight to elevate casting performance is important. Further, it is also important to improve corrosion resistance in order to prolong the face gear life span. With the conventional face gears, however, zinc alloys, which are of high relative density and are inferior in corrosion resistance, are utilized. Thus the conventional use of zinc alloys impairs lightweight design, and makes improving corrosion resistance problematic.
Therein, consideration has been given to using aluminum alloys as a face gear material for designing the face gear to be lightweight, and further, to using stainless steel alloys as a face gear material in order to improve the corrosion resistance. Due to the inferior strength of aluminum alloys compared to zinc alloys, along with inferior manufacturing precision wherein die-casting or the like is to be carried out, however, when utilizing aluminum alloys as a face gear material, the strength and precision of the teeth of the face gears deteriorates. Furthermore, while stainless steel alloys are of better strength compared to zinc alloys, owing to poor workability along with problems generally in injection molding, it is difficult to improve precision; when employing stainless steel alloys the precision of the face gear teeth is liable to deteriorate.
An object of the present invention is to achieve a method of manufacturing spinning reel lightweight face gears that ensures that the strength and precision of the face gears thus manufactured is maintained.
Another object of the invention is to provide for the manufacture of face gears of improved corrosion resistance that ensures that the strength and precision of the face gears thus manufactured is maintained.
A further object is a method of die-casting spinning-reel face gears wherein a high-strength tooth ring is formed onto a lightweight gear plate and in which high gear-meshing precision of the teeth is ensured by the casting process.
A spinning reel face gear according to a first aspect of the present invention is provided on the handle shaft of a pinning reel, and is furnished with a disk, and a tooth ring formed on the perimeter of the disk of a material different from the disk. With this face gear, because the tooth ring that is to be the meshing portion is formed of a separate material from the disk, it is possible to design a lightened face gear of improved anti-corrosiveness, maintaining its strength and precision, by manufacturing the disk with lightweight materials and materials that are anti-corrosive, and by manufacturing the tooth ring with materials by which its strength and precision are maintainable.
According to a second aspect, the spinning reel face gear is as set forth in the foregoing first aspect, and further wherein the handle shaft is formed unitarily with the disk. Herein, since the handle shaft and disk are formed unitarily, the number of parts is reduced, and the manufacturing costs and assembly costs are decreased.
In a third aspect of the invention, a spinning reel face gear is as set forth in the foregoing aspects, yet further wherein the fabrication material of the disk is aluminum alloy or stainless steel alloy, and the tooth ring fabrication material is zinc alloy or a synthetic polymer resin. Herein, the disk can be lightened and designed for improved anti-corrosiveness; moreover, manufacturing the teeth of zinc alloy or a high-strength synthetic polymer maintains teeth strength and precision.
A spinning reel face gear according to a fourth aspect of the present invention is a gear as set forth in the above-described aspects, and further wherein the tooth ring is formed on the perimeter of the disk by a post-molded insert process. Herein, the disk is specially manufactured; if the disk were otherwise formed as a single body with the tooth ring, bending and warping are liable to occur depending on the thickness and weight. Manufacturing the disk as a parent item enables forming the tooth ring by a post-molded insert process, further heightening the precision of the teeth and improving the gear-meshing precision.
From the following detailed description in conjunction with the accompanying drawings, the foregoing and other objects, features, aspects and advantages of the present invention will become readily apparent to those skilled in the art.